Technical Conditions Research Articles

LABORATORY DETERMINATION OF THE MAXIMUM DENSITY AND OPTIMAL HUMIDITY OF LARGE-BLOCK SOILS

he purpose of our field research was to develop and select a method of work on laying and compacting the material of large-block soils, ensuring the receipt and determination of maximum density and optimal soil moisture. On the basis of these studies, technical conditions for the construction of thrust prisms are further drawn up. This article presents the results of the work performed with a brief methodology of field and laboratory research. The article provides data characterizing the material intended for installation in the body of the dam. The currently existing methods for determining the control parameters of laying large-block soils are contradictory and require experimental work. A number of parameters are taken into account: grain composition, humidity, density. Therefore, the article considers a laboratory method for determining the maximum density and optimal humidity of stone material when laying in the body of the dam. The results of the research carried out on the development of our quarry area, the thickness of the uncompacted layer was determined, the choice of a sealing mechanism, the number of passes along one track, the determination of the density of dry soil in experimental field sites intended for use in filling the body of the dam, graphs of the required densities for full-scale grain composition are presented. The strength properties of the stone material were determined experimentally for the average grain composition and for the upper curve of the accepted “fish”

Environmental management of the water supply of Cidade Universitária Prof. José da Silveira Netto (UFPA) and implementation model for granting water use

This study was carried out in the Prof. José da Silveira Netto University City, on the campus of the Federal University of Pará (UFPA), on the evaluation of the environmental management of water supply and the normative status of models for granting the right to use water resources in the administrative body, the State Secretariat for the Environment and Sustainable Development (SEMAS/PA). The aim of the study is to propose necessary procedures for implementing a project to support good environmental management of urban sanitation systems, based on SEMAS/PA Normative Instruction no. 3 of March 26, 2014. The methodology was developed through documentary/bibliographical research and visits to the competent bodies (SEMAS/PA, CPRM and FEMAC) and technical visits to the sectors of the university city. The studies show that the process of environmental management of water resources and the model for granting water rights need to be improved from the outset. The water resource use on the campus of the Federal University of Pará should meet this requirement and comply with the applicable regulations and any technical conditions proposed by the competent environmental protection agency.

Central limit theorem for intrinsic Fréchet means in smooth compact Riemannian manifolds

We prove a central limit theorem (CLT) for the Fréchet mean of independent and identically distributed observations in a compact Riemannian manifold assuming that the population Fréchet mean is unique. Previous general CLT results in this setting have assumed that the cut locus of the Fréchet mean lies outside the support of the population distribution. In this paper we present a CLT under some mild technical conditions on the manifold plus the following assumption on the population distribution: in a neighbourhood of the cut locus of the population Fréchet mean, the population distribution is absolutely continuous with respect to the volume measure on the manifold and in this neighhbourhood the Radon–Nikodym derivative has a version that is continuous. So far as we are aware, the CLT given here is the first which allows the cut locus to have co-dimension one or two when it is included in the support of the distribution. A key part of the proof is establishing an asymptotic approximation for the parallel transport of a certain vector field. Whether or not a non-standard term arises in the CLT depends on whether the co-dimension of the cut locus is one or greater than one: in the former case a non-standard term appears but not in the latter case. This is the first paper to give a general and explicit expression for the non-standard term which arises when the co-dimension of the cut locus is one.

Enhancing DC distribution network efficiency through optimal power coordination in lithium-ion batteries: A sparse nonlinear optimization approach

This work deals with the problem regarding the optimal operation of lithium-ion batteries to improve the economic, technical, and environmental indices of standalone and grid-connected direct current (DC) distribution networks.To this effect, a general nonlinear programming model has been developed, which considers three objective functions: (i) the daily energy purchasing costs at the terminals of the substation, considering the maintenance costs of renewable generation (photovoltaic) and energy storage technologies (batteries); (ii) the daily energy losses associated with energy transport; and (iii) the CO2 emissions per day of operation, associated with conventional generators. This is done by integrating all the operations and technical constraints of the DC network and the devices it comprises. The sparse nonlinear optimization (SNOPT) solution method is employed, comparing its results against those of three recently reported metaheuristic optimization methodologies: the continuous genetic algorithm and the parallel versions of the particle swarm optimizer and the vortex search algorithm. The performance of the proposed methodology is validated on standalone and grid-connected networks, considering the technical and economic conditions of two regions of Colombia (rural and urban territories) and evaluating its effectiveness in terms of solution quality, standard deviation, and processing times. The results show that the SNOPT tool of the General Algebraic Modeling System (GAMS) achieves the global optimum in all test scenarios, exhibiting a standard deviation of zero and requiring less than three seconds on average to generate a solution for an entire day of operation.

Analysis of the Efficiency of Burning Briquettes from Agricultural and Industrial Residues in a Layer

The combustion of briquettes made from organic and industrial residues in small boilers requires researchers to consider the characteristics of this type of fuel and methods of its combustion. For the efficient combustion of fuel briquettes, a layered combustion method with the ability to regulate the supply of combustion air is better suited. The purpose of this research is to study the thermal technical conditions of briquetted fuel combustion. In order to carry this out, a stand was created, which made it possible to determine the combustion efficiency of this type of fuel. Two types of briquettes were studied: one with 30% sunflower husks and 70% leaves, and one with and 70% sunflower husks and 30% coke breeze. The combustion results of the briquettes show that heat loss from chemical under-burning was no more than 6.25%. To determine the temperature distribution in the fuel layer, a model of unsteady heat transfer in a fixed layer was used. A calculation of the temperature fields in the layer of burned fuel briquettes was carried out, which showed that the most favorable conditions for burning briquettes were created with a layer about 15–20 cm thick for both burned briquette options. The temperature was in the range of 450–750 °C, which on the one hand corresponds to experimental data and on the other hand provides a combustion regime that occurs with a relatively low loss to the environment. This installation and mathematical model will help future studies based on the processes of other types of organic waste combustion with a grate system.

АНАЛИЗ ОТЧЕТОВ ПО РЕЗУЛЬТАТАМ РАСЧЕТОВ ПОЖАРНЫХ РИСКОВ НА ОБЪЕКТЫ ЗАЩИТЫ ПРИ ПРОИЗВОДСТВЕ СУДЕБНЫХ ПОЖАРНО-ТЕХНИЧЕСКИХ ЭКСПЕРТИЗ ПО КРУПНЫМ РЕЗОНАНСНЫМ ПОЖАРАМ В ХОДЕ УГОЛОВНОГО И АРБИТРАЖНОГО ПРОЦЕССА

The most important aspects affecting the analysis of reports on the results of fire risk calculations performed in the framework of the preparation of special technical specifications and design documentation for warehouse facilities are considered. The analysis was performed during the forensic fire and technical investigations of fires in warehouse buildings, including those with the installed multi-tier mezzanines. The fragments of calculations included in the special technical conditions are studied and provided below. Measures aimed at improving the quality of risk calculations are proposed.

Machine Learning-Based Classification of Rock Bursts in an Active Coal Mine Dominated by Non-Destructive Tremors

Rock bursts are dynamic phenomena in underground openings, causing damage to support and infrastructure, and are one of the main natural hazards in underground coal mines. The prediction of rock bursts is important for improving safety in mine openings. The hazard of rock bursts is correlated with seismic activity, but rock bursts are rare compared to non-destructive tremors. The five machine learning classifiers (multilayer perceptron, adaptive boosting, gradient boosting, K-nearest neighbors, and Gaussian naïve Bayes), along with an ensemble hard-voting classifier composed of these classifiers, were used to recognize rock bursts among the dominant non-destructive tremors. Machine learning models were trained and tested on ten sets of randomly selected data obtained from one of the active hard coal mines in the Upper Silesian Coal Basin, Poland. For each of the 627 cases in the database, 15 features representing geological, geomechanical, mining, and technical conditions in the opening as well as tremor energy and correlated peak particle velocity were determined. Geological and geomechanical parameters of the coal seams and surrounding rocks were aggregated into a single GEO index. The share of rock bursts in the database was only about 8.5%; therefore, the ADASYN balancing method, which addresses imbalanced datasets, was used. The ensemble hard-voting classifier most effectively classified rock bursts, with an average recall of 0.74.

STABILIZING ADDITIVE FOR CRUSHED STONE-MASTIC ASPHALT CONCRETE BASED ON A LOW-GRADE PRODUCT AND WASTE FROM THE PRODUCTION OF CHRYSOTILE ASBESTOS

The results of a study of adsorption activity for bitumen and the physical and mechanical characteristics of the additive for crushed stone-mastic asphalt concrete (SMA), made on the basis of low-grade chrysotile and dusty waste from the enrichment of chrysotile-asbestos production, are presented. Structuring of the surface of layered magnesium silicates 3MgO 2SiO2 2H2O by treatment with dilute solutions of mineral acids is proposed, in which magnesium dissolution occurs only from the surface layers of magnesium silicate. At the same time, due to the structural features of the tubular structure - multilayering, the initially fibrous structure of magnesium hydrosilicate is preserved, and a layer enriched with silicon is formed on the surface of the fibers. As a result, the surface acquires a more amorphous state, which causes an increase in adsorption activity for bitumen. Based on the results of establishing the physical and mechanical characteristics of an additive made from low-grade chrysotile and powdered waste chrysotile-asbestos in the prepared crushed stone-mastic asphalt concrete mixture (ShchMAS-20), it is shown that the selected composition meets all the requirements of GOST 31015-2002 “Asphalt concrete mixtures and crushed stone asphalt concrete - mastic. Technical conditions".

Трансформация демократии в России: от представительных форм к делиберативным (правовая экспликация)

Democracy, being the basis of the constitutional system, is undergoing transformation along with other legal principles enshrined in the Basic Law. Although forms of representative democracy are currently prevalent, the author comes to the conclusion that the current technical, informational and organizational conditions contribute to the development of deliberative forms of democracy and the involvement of citizens in the process of discussing of socially significant bills.

Car-trailer coupling devices - description of requirements and overview of flexible and static load measuring solutions

The article presents an overview of the current normative, national, and international documents, containing in their content the requirements for devices coupling a car with a trailer in terms of technical conditions that these devices must meet to confirm proper performance and ensure the possibility of safe use during exploitation before will go on sale. Attention was paid to the division of coupling devices of motor vehicles and trailers into classes according to Regulation 55 of the UN/ECE and the resulting requirements. The principles according to which it should be accepted that couplings meet the approval requirements are discussed, and the meaning and way equipment manufacturers determine the characteristic values of the indicated coupling parameters are explained. Requirements for the minimum and maximum loads exerted by the trailer on the coupling device are presented. Particular attention was paid to the existing technical solutions (including patent claims in the Patent Office of the Republic of Poland or in the European Patent Office) regarding coupling devices characterized by the possibility of measuring the static vertical force on the coupling and couplings with vertical flexibility (compliance), which can potentially reduce dynamic loads on the coupling device. Calculations focused on two practical applications are planned using the article's content and simulation. The first is the ability to assess the impact of introducing vertical compliance to the coupling device on its durability. The second is the ability to assess the impact of the value of the static vertical load of the coupling device (resulting from the trailer load and the longitudinal position of its center of mass) on the length of the braking distance of the combination: towing vehicle - trailer.

Correlation among post-surgery recurrence of CRSwNP and TCM syndromes and tissue inflammatory cell infiltration type: a study protocol

BackgroundFunctional endoscopic sinus surgery is a principal option for treating chronic rhinosinusitis with nasal polyps (CRSwNP) after medication failures. Unfortunately, some patients still have unsatisfactory postoperative recovery. The type of inflammatory cell infiltration in nasal polyp tissue has been reported available for recurrence prediction. As it is invasive and time-consuming, this technique is hard to promote clinically under the existing technical conditions. And during the course of clinical treatment, we have noted that differences in the postoperative recurrence rate of patients present among different traditional Chinese medicine syndrome types.Methods and analysisThis is a non-randomized, single-center, and prospective cohort study started in Chengdu Sichuan Province, People’s Republic of China, in January 2021. A total of 200 participants will be recruited from patients who are diagnosed with CRSwNP and prepared for functional endoscopic sinus surgery. We collect preoperative data which includes general information, medical history, TCM syndromes, visual analogue scale (VAS) of subjective symptoms, Lund-Kennedy endoscopic score, and Lund-Mackay score of computed tomography (CT) scanning of sinuses. We acquire the VAS score and Lund-Kennedy score of subjective symptoms through multiple planned follow-up after surgery. After 1 year of follow-up, the recurrence rate will be calculated, and the curative effect will be assessed. Meanwhile, the patients’ pathological sections will be sorted out, and inflammatory cell infiltration will be analyzed. Statistical analysis will be carried out to evaluate the correlation among CRSwNP recurrence and TCM syndrome types and tissue inflammatory cell infiltration types. Then we will establish a predictive model for CRSwNP recurrence. Analyses of survey data include descriptive and inferential statistical approaches.DiscussionThis is the first prospective cohort study on investigating the correlation of CRSwNP recurrence with TCM syndrome types and tissue inflammatory cell infiltration types. Through this study, we hope to discover a new and simple, effective, and noninvasive way to predict the recurrence rate rapidly after CRSwNP and provide reference for the intervention timing of traditional Chinese medicine application, thereby achieving customized diagnosis and treatment, minimizing risks of surgical events, and delaying postoperative recurrence of CRSwNP.Systematic review registrationPROSPERO ChiCTR2100041646.

PRACTICAL ASPECTS OF DEVELOPING SKILLS AND ABILITIES OF INDEPENDENT WORK OF FUTURE HISTORY TEACHERS

An important task of the educational process in a higher institution of pedagogical education is the purposeful formation of the readiness of students ‒ future teachers for professional self-education as a comprehensive characteristic of their personality, which includes the needs and motives of self-education, professionally significant qualities, as well as necessary knowledge, skills and abilities. A student’s ability to self-education is developed in the process of learning. Self-education skills require purposefulness, systematicity, consistency, and self-motivation of the subject of education. One of the factors contributing to the development of this ability can be research and creative tasks for independent performance in the content of methodological disciplines.The article reveals various types of independent work aimed at the formation of self-educational competence of higher education students, the ability to learn throughout life. Examples of practical tasks from the course “Theory and teaching methods of civic education” are given, which form cognitive and operational- procedural components of the independent activity of higher education students. In the course of the study, the technical conditions for the performance of the tasks, their procedural characteristics, and examples of the implementation of metacognitive strategies in the formation of the subject-methodical competence of future history teachers are given. It was found that independent work allows students to build their educational and professional trajectory and is an area of mutual responsibility of subjects of the educational process.

Embodying parkour’s visual subculture: ethos, style and the emergence of a visual habitus

This article describes parkour's visual subculture as a form of subcultural capital that has developed with the rise of this alternative sport. It examines the recent history of its visual media as well as a visual habitus to understand the ways in which a collective gaze is produced and performed. Furthermore, the text locates the parkour practitioner – the traceur – as a key actor of an aesthetic system, a relatively autonomous figure that embodies an underlying visual symbolic structure and mobilizes a scopic system through different interactions with social media. By analysing three key elements through which traceurs have developed a visual tradition and a corresponding ethos, this article seeks to explain how parkour has been adapting to changing technical and sociocultural conditions, showing thus the complexities and nuances of a sophisticated visual world.

«Цифра» и суверенность в современной российской образовательной политике

The article presents an analysis of the contradiction that todaycharacterizes the stateinitiative for the transition of Russian education from the Bologna format to “sovereign” and “unique” functioning. This is a contradiction between the plans for accelerated digitalization of the educational sphere and, at the same time, for it to acquire certain qualities that are unique nowhere else in the modern world. Arguments are given in favor of the fact that attempts by subjects of Russian educational policy to give constructive meaning to the ideas of sovereignty of education in our country and its achievement of a state of uniqueness will face the objective need to sacrifice sovereignty and uniqueness for the sake of fulfilling the technical conditions of digitalization. The article predicts the expected risky consequences of such a conflict of meanings and goals in the ideology of planned educational reforms for state educational policy.

Preparation and Properties of Temperature Resistant and Salt Resistant Lotion Fracturing Fluid Thickener

In order to prepare fracturing fluid with excellent solubility, temperature resistance, salt resistance and shear resistance, acrylamide (AM), 2-acrylamide-2-methylpropanesulfonic acid (AMPS) and acryloylmorpholine (ACMO) were copolymerized, and anionic cellulose was introduced to synthesize a new type of polyacrylamide copolymer p (AM/AMPS/ACMO) through inverse emulsion polymerization. The structure and morphology were characterized by infrared spectroscopy and scanning electron microscope. The results showed that in 0, 5, 10, 20, 50, 100, 150 and 200 g/L NaCl, CaCl2, and MgCl2 solutions, the viscosity of p (AM/AMPS/ACMO) solution modified by PVA fiber was always higher than that of conventional PAM solution, and the polymer modified by PVA fiber had better salt resistance. The anionic cellulose modified thickener was sheared at 120 ℃ and 150 ℃ for 1 h at 170 s－1, and the viscosity after shearing is 89.92 mPa·s and 80.10 mPa·s, respectively, which is much higher than the viscosity required by the general technical conditions of fracturing fluid more than 50 mPa·s, indicating that anionic cellulose modified p (AM/AMPS/ACMO) has good temperature and shear resistance.

Использование сахарозаменителей при производстве сдобного печенья из цельнозерновой муки

The purpose of research is to study the effect of sugar substitutes on the quality of butter cookies made from whole grain flour. Objectives: to justify the need to develop cookies from whole grain flour and sugar substitutes; conduct test baking and develop a recipe for butter cookies made from whole grain flour and sugar substitutes; to investigate the effect of whole grain flour and sweeteners on the quality of finished products in various dosages. The quality of butter cookies was assessed based on organoleptic indicators in accordance with GOST 24901-2014 “Cookies. General technical conditions". Humidity was determined according to the method described in GOST 5900-2014 “Confectionery products. Methods for determining moisture and dry substances”, Methods for determining moisture and dry substances”, wetness – according to GOST 101114-80 “Flour confectionery products. Methods for determining wetness", alkalinity of cookies – according to GOST 5898-2022 "Confectionery products. Methods for determining acidity and alkalinity". A cookie recipe was developed in which premium wheat flour was replaced with whole grain flour and instead of white sugar; Fit-Parad № 7 sugar substitutes were used. Test baking was carried out in the laboratory-bakery of the Department of Food Technologies of the State Agrarian University of the Northern Trans-Urals. The results of an organoleptic assessment of the quality of butter cookies made from whole grain flour with sugar substitutes are presented. The addition of the Slim-Vit sweetener with vitamin D in an amount of 5 and 7 g to the flour mass improved the taste and smell: the balance of the combination of the sugar substitute with whole grain flour is felt. The addition of the sugar substitute Fit Parade № 7 in the amount of 5 and 7 g to the weight of flour did not have any particular effect on the organoleptic characteristics compared to granulated sugar. Physicochemical parameters were determined by standard analytical methods. The physicochemical parameters of a control sample and using whole grain flour and two types of sugar substitutes were studied. Whole grain flour absorbs more moisture and has a higher sogginess compared to premium wheat flour. Replacing granulated sugar with sweeteners did not affect the physicochemical parameters.

The Collapse of the Vaults of the Ambato Matriz Church in the 1949 Earthquake: A Response with a Technical Approach

This research examines the structural behavior of the central vault of the Matriz church that collapsed during the 1949 earthquake in Ambato, Ecuador. Following the disaster, the church and Episcopal Palace were demolished. The central vault lacked buttresses and had large cracks two years before the collapse. A study was conducted using graphic restitution and the theory of limit analysis of structures to analyze the mechanical behavior of the central vault. The aim was to provide a technical explanation for the cause of the collapse beyond the impact of the earthquake. The limit analysis of structures is a tool that determines the technical stability conditions of a masonry structure using graphic statics. In this case, the respective checks of the structural behavior could be made, concluding that the structural ensemble of the central vault was unstable and could have collapsed at any moment, not necessarily due to an earthquake. The article is based on the research project “Architectural analysis of the central nucleus of Ambato between 1895 and 1949: styles, types, techniques, losses, and continuities”, which was conducted at the Universidad Técnica de Ambato, Ecuador, from 2021 to 2023.

The ANALYSIS of the MECHANICAL PROPERTIES of REGIONAL PIPELINES

Piston pumps and compressors are widely used for exploration and transportation of oil and gas. Piston machines are heavy-duty systems that are still failure prone due to high stresses and wear proses. Increasing the efficiency and durability of the piston compressors, pumps, internal combustion engines, etc. directly depends on the correct calculations and designing of these elements. Using ANSYS software, simulation and stress analysis are performed on the basis of the 405GP15/70 and ARIEL heavy-duty balanced opposed piston compressors used in the Caspian Sea-Black Sea Region. During working of the machines and equipment a number of the processes interconnected and causing each other are proceeds (dynamic processes, wear of the interfaced details, change of mechanical properties of materials, etc.). Improvement of modelling of technical condition of cars and mechanisms on a multicriteria basis is one of the actual directions of modern engineering science. The improvement of methods of modelling of change of technical conditions of the piston mechanisms taking into account interrelation of dynamic characteristics, the wear interfaced details and the diagnosed mechanical parameters considered in this article. By observing the analysis results, we can decide whether our designed pipelines are safe or not under applied load conditions. The durable and reliable work of compressor-pump stations used in the oil and gas industry has great importance for practice. Investigation of complex problems with respect to friction and wear (clearances), stresses, and thermodynamics phenomena in the piston machines, and oil and gas pipelines gives the opportunity to solve the problems of increasing the durability of these machines and pipelines. Confirmation that the new methodologies can be produced by the current supply chain improving manufacturing efficiency and reducing the environmental and social impact of the supply chain.

Analyzing EV User Behavior in Aggregator Smart Charging with ESS and Real-Time Pricing

Amidst increasing global electricity consumption, governments prioritize energy efficiency and electric vehicle (EV) integration into energy markets. This study examines EV aggregator strategies employing smart charging methods, adjusting charging rates based on user preferences. Through simulations in Quito's distribution system, it analyzes actions' effects on aggregator costs and technical conditions, with a focus on demand response (DR) strategies, particularly in residential areas. Exploring EVs' potential as energy storage via vehicle-to-home (V2H) and vehicle-to-grid (V2G) options, the study introduces a collaborative evaluation of dynamic pricing and peak power limiting-based DR strategies, integrating bi-directional EV and energy storage system (ESS) use. It also proposes a novel mixed-integer linear programming (MILP) model for home energy management (HEM), incorporating distributed renewable energy, V2H/V2G capabilities, two-way ESS energy trading, and diverse DR strategies. This comprehensive approach assesses the impact of EV owner preferences and ESS availability on reducing total electricity costs through case studies.

Technical and Economic Performance Assessment of Solar Milling Plants in Zambia

In 2015, the Zambian government embarked on a proactive endeavor to enhance the accessibility of economical maize meal through the inception of the Solar Powered Milling Plants (SMPs) Project. The Chinese Government and the Government of the Republic of Zambia jointly provided co-financing, supporting this audacious initiative with a significant financial commitment of US$200 million. However, there have been no documented results on the technical and economic performance of the solar milling plants. To this effect, this study aimed to establish the technical and economic performance of the milling plants installed by the Zambia Cooperative Federation. To achieve this, the study sought to: (1) establish the technical operational characteristics of the installed SMPS; (2) establish the factors that influenced the sitting of the plants; (3) determine the economic benefits of the SMPs; and (4) benchmark the technical operating conditions of the installed SMPs. The study employed a mixed methods approach, where benchmarking observations and semi-structured questionnaires were used as data collection instruments. The sample size of the study was 168, comprising cooperative leaders, solar milling plant operators, and community members from the 12 sites in Masaiti, Chikankata, Solwezi, and Kapiri Mposhi districts where the milling plants were installed. The field observations and questionnaires that were used for the study showed that all twelve sites in the Solwezi, Masaiti, Kapiri Mposhi, and Chikankata Districts needed the same amount of power to run, which was between 7.5 kW and 9.0 kW. However, only Site 3 in Solwezi and Sites 4 and 5 in Masaiti Districts strictly followed the standard operation time of 8 hours. The study has also shown that the two main factors that influenced the placement of the solar milling plants were proximity to the main roads of the communities and the availability of land near the Food Reserve Agency(FRA) shades. With regards to economic benefits, the generated results showed that the installed milling plants brought about employment creation as two operators were employed for each of the 12 sites. However, the revenues generated by the solar milling plants were not economically viable for loan repayment. The study recommended that predictive and corrective maintenance, in addition to project management training for cooperatives and operators, be carried out to improve the technical and economic performance of the solar milling plants.